What the bjerrum??

So I tried to do this homework problem where we calculate the horizontal forces contributing to ridge push. Just a simple little calculation based on the differences in pressure calculated at some compensation depth beneath the ridge and at some distance away from the ridge. No problem. Imagine my surprise when I discovered that instead of the plates being pushed apart at the ridge, they are in fact being pushed together. Which breaks several laws of physics, and doesn’t match observations either. Brilliant!

Now, back to practicing my presentation. Look out fin whales! You will be counted! (To some statistically quantified uncertainty level!)